Comparison of Efficiency

Author: E.E. Kimberly

In an incandescent gas-filled lamp, 60 to 75 per cent of the energy is radiated as heat. In a fluorescent lamp, only about 25 to 35 per cent of the energy is radiated as heat. Because the efficiency of light production of fluorescent lamps is about double that of filament lamps, and because the per cent of radiated heat is only about half as much, the sensation of heat from a fluorescent lamp is only about onefourth that of a filament lamp for the same light output. Fluorescent lamps may be operated economically on any voltage within 6 per cent above or below rated voltage, but their efficiency decreases at higher voltages. With present types of auxiliary equipments, they are not suited to flashing or dimming applications. They operate most efficiently in temperatures between 70 and 80 F, and are likely to develop starting difficulties in refrigerated show cases or in outdoor applications in winter.

In general it may be stated that, if the color of light is not important, filament lamps are more satisfactory than fluorescent lamps where the illumination needed is low or moderate and the use is intermittent. The fluorescent lamp is more satisfactory where the intensity must be high and the lamp is burned many hours with few starts.